Abstract

An organic complementary metal–oxide–semiconductor (O-CMOS) inverter is presented, which is based on a single pentacene layer acting both as - and -type organic semiconductors. The circuit consists of two spatially separated transistors realized by pairs of calcium and gold source and drain electrodes, respectively. The transistor is obtained by utilizing the conventional channel interface whereas the transistor is realized by doping the interface with traces of calcium prior to pentacene deposition. Both, and transistors work exclusively in unipolar mode within the range of the supply voltage of 60 V. The O-CMOS inverter works reliably with a gain in between 17 and 24, and the respective electron and hole mobilities were found around . The circuit shows hysteresis, which can be explained by a gate voltage-dependent electron trapping in the channel. Electron accumulation can also be realized by the application of a polymethylmethacrylate interlayer between and pentacene.